Final Site Information Package for National Remedy Review Board ...
Final Site Information Package for National Remedy Review Board ...
Final Site Information Package for National Remedy Review Board ...
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6. Summary of Risks<br />
The Bunker Hill Superfund <strong>Site</strong> was listed on the NPL in 1983 based upon high levels of<br />
lead, arsenic, cadmium, and zinc in the local environment and high blood lead levels in<br />
children living in communities near the smelter complex and related mining activities. In<br />
the 1970s lead poisoning was widespread, with 75 percent of children exceeding a blood<br />
lead level of 40 micrograms per deciliter (µg/dL). The health response has been ongoing <strong>for</strong><br />
decades, and now area children have blood lead levels close to the national average.<br />
Historical mining wastes have created a legacy of pervasive elevated metals concentrations<br />
that present significant measureable risks to many animals and plants throughout the Basin.<br />
The risks are neither hypothetical nor potential future risks—the risks continue to exist<br />
today.<br />
Public health studies and epidemiologic and environmental investigations begun in the<br />
1970s concluded that atmospheric emissions of particulate lead from the active smelter were<br />
the primary sources of elevated blood lead levels in local children from the populated areas<br />
of the Bunker Hill Superfund <strong>Site</strong>, later known as OU 1 of the Bunker Hill Box. Associated<br />
risks to human health were evaluated through the 1990 Risk Assessment Data Evaluation<br />
Report <strong>for</strong> the populated areas (OU 1) (“the RADER,” USEPA, 1990) and in the 1992 Human<br />
Health Risk Assessment (HHRA) <strong>for</strong> the non-populated areas (OU 2) (SAIC, 1992). The<br />
RADER evaluated both carcinogenic and noncarcinogenic effects of contaminant exposures.<br />
The non-populated areas HHRA evaluated exposures either as baseline (resulting from<br />
activities common to all members of the resident population) or as incremental (resulting<br />
from potentially high-risk activities by some members of the local population or visitors to<br />
the area).<br />
Human health risks were further evaluated in the HHRA <strong>for</strong> the Coeur d’Alene Basin in<br />
2001 (Idaho Department of Health and Welfare [IDHW], 2001). The results of this HHRA<br />
were summarized in the 2001 NRRB Presentation <strong>In<strong>for</strong>mation</strong> (USEPA, 2001b; see<br />
Supplemental CD, File B2-1). Subsequently, the ROD <strong>for</strong> OU 3 (USEPA, 2002) summarized<br />
the results of a baseline HHRA of the Harrison to Mullan portion of the Upper Basin<br />
(exclusive of the Bunker Hill Box, which was addressed in prior OU 1-specific risk<br />
assessment reports), which includes all of the Upper Basin study area. An EcoRA (CH2M<br />
HILL and URS Greiner, 2001) was prepared as part of the RI/FS <strong>for</strong> the Coeur d’Alene<br />
Basin. The EcoRA characterized risks to aquatic and terrestrial organisms exposed to<br />
hazardous substances associated with mining activities. A focused EcoRA was completed in<br />
2006 to evaluate the effects of lead-contaminated soil on groundfeeding songbirds in the<br />
riparian area of the Basin (CH2M HILL, 2006b).<br />
As reported in CERCLA Five-Year <strong>Review</strong> Reports prepared <strong>for</strong> the Bunker Hill Superfund<br />
<strong>Site</strong> (USEPA, 2000a, 2000c, and 2005), selected human health remedies that have been<br />
implemented within the Upper Basin communities to date are protective, and they are<br />
functioning as designed. However, elevated concentrations of mining-related metals in<br />
surface water, soil, sediments, and biotic tissues continue to pose risks to people and to the<br />
survival and growth of animal and plant species. The Five-Year <strong>Review</strong> Reports concluded<br />
B6-1